"It's been a real privilege to be associated with the North Queensland Cowboys and now that the deal is done, I can concentrate on my footy and helping my teammates on and off the field."

Cowboys coach Paul Green said Thurston's playing record and achievements spoke for themselves, but added he was most pleased with how one of the game's best players continually strove for improvement in life and in football.

"Johnathan's a class act, is one of the fiercest competitors I've seen play rugby league and to have him see out his career here is wonderful news and a credit to all involved," Green said.

"He's developed into a true leader in that he leads by example. He's always a pleasure to coach and he's a true mentor for our younger guys coming through."